As a redshirt freshman in 2003, Ramírez started 10 games, making his first start against SMU and capped off the season with a start in the 2003 Houston Bowl. During the next three years, he started all 36 regular season games along with starts in the 2004 Holiday Bowl, the 2005 Cotton Bowl Classic and the 2006 Insight Bowl. Ramírez was named a 2nd Team All-Big 12 Offensive Lineman in 2005.[2] Ramírez began the 2006 season on the Outland Trophy Watch list in 2006, and was named to the All-Big 12 Preseason First Team.[3] He concluded the 2006 season being named to the All-Big 12 Honorable Mention Team.[4]

He set the school bench press record in 2003 by pressing 525 pounds. Ramírez tied that record the following year. In 2005, Ramírez broke his own bench press record by pressing 550 pounds at the Annual Texas Tech "Night of Champions".

Ramírez finished 2006 on an offensive line that allowed the fewest sacks, 16, since the 2000 season.

Ramírez played in the 2006 Insight Bowl which saw the biggest comeback in NCAA Division-I bowl history.[5] The Red Raiders overcame a 31-point third-quarter deficit to beat their opponent by 3 in overtime. The winning touchdown was a 3-yard run from Shannon Woods behind a block by Ramírez.

Ramírez was selected by the Detroit Lions with the 18th pick in the 4th round of the 2007 NFL Draft. Detroit traded two of their three fifth-round selections (139th and 154th overall) to the St. Louis Rams for their fourth-round selection (117th overall) in order to select Ramírez. In October 2010, Ramírez was named the Detroit Lions starting right guard.

In 2013, Ramírez won the starting center job after Dan Koppen tore his ACL during training camp.[8] On September 12, 2013, he signed a two-year contract extension with the Broncos.[9] In Super Bowl XLVIII, Ramirez could not hear the play call of Peyton Manning, which resulted in Ramirez snapping the ball early, over the head of Manning, into the end zone for a safety and giving the Seattle Seahawks a 2-0 lead 12 seconds into the game.[10] The Broncos would not recover and would go on to lose the game, 43-8.[11]

On April 30, 2015, Broncos traded Ramirez, as well as, their first and fifth-round 2015 NFL draft selections (28th and 143rd overall, respectively) and their fifth-round selection in the 2016 NFL draft for the Detroit Lions' first round pick in the 2015 NFL draft (23rd overall) in order for Broncos to select linebacker Shane Ray.[12] The Lions in turn selected offensive lineman Laken Tomlinson with the 28th pick.